A typical lithographic plate includes features such as flanges and openings that enable the plate to be mounted on a printing plate cylinder of a printing press. The configuration of these flanges and openings defines the alignment between plural plates installed on a printing press and provides the registration of the various colors of the printed image. Accordingly, precision metal working techniques for bending such flanges and forming such openings are used to ensure precision alignment between plural plates mounted on a printing press.
A typical machine used for forming a precision bend in a lithographic plate includes an anvil provided at the end of a supporting surface, a clamping device for clamping a plate to be bent to the supporting surface, and a mandrel for bending the plate around the anvil to form a flange. The anvil has an end with a forming surface that has a predetermined radius and a bend is made by rolling the plate around the radius of the forming surface of the anvil. In this way, the material of the plate conforms to the shape of the anvil to form a bend radius in the flange that is defined by the radius of the forming surface of the anvil. Exemplary machine tools for bending lithographic plates are described in U.S. Pat. No. Re. 31,938, reissued Jul. 9, 1985, to Klukow, U.S. Pat. No. 5,970,774 to Burgess et al., and U.S. Pat. No. 5,454,247 to Powers et al., the disclosures of which are incorporated herein by reference in their entirety for all purposes.
Lithographic plate bending machines, as presently known, suffer from certain limitations. Printing presses made by different manufactures have lithographic plate receiving slots that require lithographic plates with mounting flanges having angles and bend radiuses different than those of other manufacturers. This requires the printer to either have multiple benders each with an anvil having an angle and radius unique to the printing press on which the lithographic plate is to be mounted or to remove and replace the anvils each time a lithographic plate is to be bent for a different printing press.